feat: add @Order to ApplicationReadyEvent listener (#3151)

[WeisSebastian]

Adresses #3151

Add @Order to the ApplicationReadyEvent listener introduced in 2.8.14. This allows consumers of the library to define in what order the listener is executed. Without this annotation, the listener is executed after all other listeners that do have the @Order annotation.

Note: The range of int signalling the Order is from Integer.MIN_VALUE to Integer.MAX_VALUE with a lower value meaning a higher priority, so 0 seems to be a sensible value for me